I tried doing a "repeats" style workout tonight on the treadmill. I can manage the speed that I am going, which is appealing to me. I want to do this type of workout on the track too, but there aren't a lot of them nearby. Notation is weird, I don't know how to write these down. Felt pretty good, like this was a quality workout. Fast runs were much faster than my normal pace, at least 1 min/mile faster than my fastest pace outside so far.